The general concept of providing a double or dual containment pipe system wherein an inner carrier pipe is concentrically located within an outer containment pipe to deliver dangerous or hazardous fluids is well known and an accepted commercial practice. Historical applications for such systems have been found in the nuclear, gas petroleum production and refining, and chemical processing industries. The inner pipe is used to transport hazardous or toxic fluid while the outer pipe is present to confine any leaks. Thus, it is also known to provide the annulus between the concentric pipes with various types of detectors and/or drainage apparatus to handle leakage.
A problem with existing systems has to do with the ability to combine different inner and outer pipe materials in an efficient manner. Different materials, or dissimilar materials, can mean materials that are of a different class (such as metallic-thermoplastic, metallic-reinforced thermosetting plastic, or thermoplastic-reinforced thermosetting plastic), or materials that are within the same class but constitute a different material, (such as within the thermoplastic family, combining a fluoropolymer within a polyolefin, or a polyolefin within another polyolefin). The reason that it is desirable to combine materials typically has to do with economics. It is desirable in many situations to combine an expensive material that is capable of handling a chemical on a full time basis within a less expensive material capable of withstanding the corrosive effects of a chemical for a limited period of time. Another major economic reason has to do with the use of a material for the outside piping capable of withstanding the corrosive effects of atmospheric conditions, thus eliminating the need for expensive coatings, cathodic protection, etc. A typical example of this would be in combining a metallic material within a nonmetallic outside material for the reasons just described. Yet a third reason has to do with structural concerns, such as where a non-metallic material is housed within a metallic outer jacket, for purposes of protecting a pipe that is buried to shallow depths from possible large “live loads” due to vehicular traffic on the ground surface.
A termination fitting is used to terminate, or end, an outer pipe while allowing the inner pipe to continue. When the inner and outer pipes are made from the same material, the termination fitting can be welded to each pipe in order to accommodate high-pressure uses for the double-containment system. However, when the inner and outer pipes are made from dissimilar materials, the termination fitting cannot be welded to each pipe in order to accommodate high-pressure uses for the double-containment system.
What is still desired is a new and improved termination fitting for a double-containment system. Among other advantages and benefits, the new and improved termination fitting will preferably be useable with double-containment systems of dissimilar materials and accommodate high-pressure uses for the double-containment system.